Five years ago, B-1 aircraft availability rates reached a historical low point. But thanks to the maturation of the bomber’s upgrade program, the timely assistance of stopgap civilian maintainers, and a recent increase in military manpower, B-1 availability is rebounding.

By the time the Air Force completes the Block 16, or integrated battle station (IBS) upgrades in 2020, the service expects availability rates for its fastest, heaviest-lifting bomber to improve even more, Col. Robert Lepper, chief of the combat aircraft division at Air Force Global Strike Command, told Air Force Magazine.

The largest-ever modification of the B-1 began in 2012 as an effort to improve the sustainability and operational ability of the entire BONE fleet. IBS includes three major changes, said MSgt. Brian Hudson, manager of B-1 avionics at AFGSC. First, the installation of a central integrated test system provides the B-1 with “a real-time and diagnostic recording system.” A new fully integrated data link allows the bomber to “interface with a global network of DOD assets via satellite network.” And a new visual display enables B-1 operators to see and incorporate targeting data communicated from other aircraft and sensors.

The goal of the IBS upgrade is ​twofold. First is “sustainment,” Lepper said. The Air Force wants to extend the life of the B-1 as long as it can. But IBS also provides “significant enhancements for situational and operational awareness”—that is, it allows the B-1 to play well with younger, more advanced aircraft, including the fifth-generation F-35 strike fighter.

In early 2016s, USAF pulled its B-1s operating in the US Central Command area of operations home for modifications, marking the first time since 2001 the type took a break from the fight in the Middle East. The Air Force is now approaching the halfway point of the upgrade program. Twenty-nine of the service’s fleet of 62 aircraft have put in their time at Tinker AFB, Okla., where the upgrade work is being done. AFGSC expects to upgrade the remaining 33 B-1s by May 2020, Lepper said.

With an expected duration of 218 days, the IBS work puts a significant dent in B-1 aircraft availability rates. Lepper said the Air Force planned for a 10 percent reduction in AA during the upgrade period, and the service is close to that number now. At any given moment, six aircraft are removed from fleet availability as they go through various stages of the upgrade, but Tinker is getting faster. The last five upgrades were completed in an average of just 187 days, Lepper said.

Other issues have lowered B-1 AA rates recently as well.

“Several years ago we found cracks in a fuel tube,” Lepper said. The problem requires AFGSC to perform additional “extensive inspections on them every 90 sorties.” Those inspections make an aircraft unavailable for an entire week. The fix, which includes “brand new fuel tubes,” is set to begin arriving in July, and AFGSC expects to repair the entire fleet by the end of 2019.

Also, because of the age of the aircraft, “full scale fatigue testing” has impacted AA rates. “Based on the number of flying hours we put on the aircraft,” Lepper said, “we have found indications of cracks, so we do a lot of inspections to make sure we are looking for and identifying cracks before they become a problem to the fleet.”

Lepper said the fuel tubes reduce the AA rate by about three percent, while fatigue testing brings a four-to-five percent hit.

Overall, he is not concerned that the AA rate for the B-1 has averaged only 41 percent over the last 10 years, according to statistics USAF provided to the House Armed Services Committee in March.

“As long as we can understand what’s causing our lower availability, then we have an opportunity to impact it,” Lepper said.

In the last five years the service has “been making consistent improvements to get better in the B-1,” he said. First, AFGSC “hired some civilian technicians to help us in the B-1 arena while we were going through low manning,” and more permanent help is also on the way.

“We have fortunately just added almost 250 maintenance positions to the B-1,” Lepper said, and “those people are coming on board right now.”

As more rejuvenated B-1s come online, the upgrades are also helping the AA picture because they offer “improvements in aircraft reliability and sustainment,” he added. AFGSC expects the completion of the IBS program to bump the B-1 aircraft availability rate by 10 percent, and with the new maintainers, “we see the potential to make a two or three point jump” in the meantime, Lepper said. ​

The hope is that with increased availability and an extended lifespan, the B-1 will remain “a significant deterrent to our adversaries across the globe” for years to come, he noted.